Extreme pressure lubricants



United States Patent 3,344,065 EXTREME PRESSURE LUBRICANTS iosef Gansheimer, Munich-Gbermenzing, and Oswald Schanzer, Munich, Germany, assignors to Molykote Produktions G.m.b.I-I., Munich, Germany No Drawing. Filed Jan. 25, 1965, Ser. No. 427,950 4 Claims. (Cl. 252-18) ABSTRACT OF THE DISCLOSURE An extreme pressure lubricant is prepared by addition of both a solid lubricant and any of certain metal salts of phosphorated oxygen acids to a mineral or synthetic lubricant.

This invention relates to novel lubricants and particularly to unique extreme pressure lubricants giving superior lubrication under severe conditions.

The compositions set forth herein are based on known lubricating bases such as mineral and synthetic oils and greases employed as lubricants. It is known that the addition of solid lubricants such as molybdenum disulfide to known liquid lubricants may greatly improve the loadcarrying capacity of the lubricant oil. Thus extreme pressure lubricants frequently contain solid lubricants such as molybdenum disulfide and Wolfram disulfide. German Patent No. 1,090,804 teaches the use of alkali metal phosphates and/ or alkaline earth metal phosphates as additives to lubricants to improve the extreme pressure lubricating properties.

It is the primary object of this invention to introduce a novel extreme pressure lubricating composition. A further object is upgrading mineral and synthetic lubricating oils to impart extreme pressure lubricating characteristics thereto. Other objects and advantages of this invention are detailed in or will be apparent from this application.

This invention comprises an extreme pressure lubricant based on mineral or synthetic lubricating oils and lubricating greases containing solid lubricants, particularly those solid lubricants having laminar structure, in combination with metallic salts of phosphorated oxygen acids which are essentially insoluble in water.

The treatment of metals with aqueous bonderizing baths is known. This bonderizing treatment forms a layer on the metal surface providing effective lubrication. The excess bonderizing agent is removed and the metal is dried after the bonderizing treatment in the aqueous bath. The bonderizing of metal surfaces involves the use of an extremely strong aqueous acid bath which must con tain uncombined phosphoric acid in concentrations of about to 50 percent by weight.

The bonderizing treatment produces a surface layer on the metal which provides effective lubrication over a short period of time but such treatment does not provide a lifetime or permanent lubrication. Thus it could not be inferred from the known bonderizing treatment that the use of metallic salts of phosporated oxygen acids which are insoluble in water as additives to known mineral and synthetic oils and greases containing known solid lubricants would produce a novel and highly eliective extreme pressure lubricant. The new extreme pressure lubricants so prepared do not require the presence of uncombined acids as is required in the bonderizing process.

The compositions of this invention must contain three components, namely: (1) a mineral lubricating oil or grease or a synthetic oil or grease; (2) a solid lubricant; and (3) the water insoluble metal salt of phosphorated oxygen acids.

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The first component is any of the known bases for lubricants. These lubricants are essentially anhydrous and may have any consistency from thin fluid to heavily loaded greases which appear to be hard waxes. Dispersing agents may be contained in the lubricant to insure even and thorough distribution of the solid additives including the solid lubricant (2) and the metal salt additives (3) throughout the base lubricant. Thorough and even distribution of the extreme pressure metal salt additive (3) is required to minimize settling out or sedimentation of the additive and to secure the best possible extreme pressure characteristics. Suitable base lubricants include mineral oils, mineral greases, alkali metal soaps of high fatty acids, natural and synthetic waxes, including beeswax, carnauba wax, oxide waxes, ceresites, ozocerites and others, synthetic lubricating oils based on polyisobutenes, polyglycols, polyesters, phosphoric acid esters, fluorocarbons, silicones, silicate esters, polyphenylether and others.

The solid lubricants employed herein are any of those known solid substances providing effective lubrication. Particularly known for this use and employed herein are heavy metal sulfides as exemplified by M08 and W8 selenides and tellurides of Mo and W, graphite, hydroxides of Ca, Li, Mg, Cd, Fe, Co, Ni, and Mn, calcium cyanamide, halides of Mn, Ca, Cd, Zn, Fe and Co and similar solid lubricants as well as mixtures thereof.

The metal salt of phosphorated oxygen acid which is insoluble in water can be derived from the acids of the electropositive pentavalent or trivalent phosphorous. The salts can be derived from monomeric phosphorous and *orthophosphoric acid as well as from condensation products and/ or oligomeric and polymeric phosphorated oxygen derivatives such as pyrophosphoric acid, orthophosphoric acid, hypophosphoric acid, phosphorous acid, hypoand pyro-phosphorous acids and meta-phosphoric acid. Generally preferred are the phosphates of aluminum, manganese, zinc, iron, magnesium, barium, calcium, boron, cadmium, copper and lead which are at most only slightly soluble in water.

In general, the solid lubricants and the metallic salts of phosphorated oxygen acids are employed in proportions of from 0.5 to percent by Weight 'based on the weight of the total lubricant composition and the preferred range of said additives is from 3 to 60 percent by weight on the stated basis. The metal salts of phosphorated oxygen acids are employed in proportions of from 2 to 50 percent by weight, preferably 5 to 25 percent, based on the weight of the metallic salt and solid lubricant employed.

By way of example and not limiting the scope of the invention, some lubricants according to this invention are described in the following examples. The tests were carried out on the four-ball apparatus and on the Almen- Wieland machine and the essential improvement of the lubricating properties of the combination according to this invention is compared with the lubricants containing only one component in the same quantity.

Example 1 Oils: Four-ball apparatus, kg. (at) Mineral oil Mineral oil+5% phosphate of iron 340 Mineral oil+5% molybdenum disulfide Mineral oil+2.5% phosphate of iron+2.5%

molybdenum disulfide 480 (b) Mineral oil 100 Mineral oil+;5% phosphate of aluminium 100 Mineral oil+5% molybdenum disulfide 180 Mineral oil+2.5% phosphate of aluminium +25% molybdenum disulfide 280 3 Example 2 Pastes: Almen-Wieland machine, plates (a) Mineral oil 4 Mineral oil+25% molybdenum disulfide 38 Mineral oil+25% phosphate of aluminium 7 Mineral oil+12.5% molybdenum disulfide +12.5% phosphate of aluminium 40 (b) Mineral oil 4 Mineral oil+25% WS 37 Mineral oil+25% calcium phosphate 17 Mineral oil-142.5% WS +12.5% calcium phosphate 40 Elongation of shaft.

Example 3 Greases: Almen-Wieland machine, plates (a) Lithium base grease 12 Lithium grease+30% phosphate of aluminium 36 Lithium grease+30% calcium hydroxide 25 Lithium grease-[-15 phosphate of aluminium 1 calcium hydroxide 40' Elongation of shaft.

Almen Wieland Founball ap. machine paratus kg. 1

(b) Lithium base grease 12 plates 140 Lithium grease+4% M082... 39 plates 240 Lithium grease +4% phos. 35 to 36 plates... 300

phate of aluminum. Lithium grease+2% phos 38 plates 340 hate oi aluminum+2% 1032.

1 Permissible load before fretting occurs.

Example 4 Equivalent improvement was achieved when Example 1 was repeated employing a silicone lubricant, a polyester lubricant, a phosphoric acid ester or an alkali metal soap of lauric acid as the lubricant.

Example 5 Equivalent improvement was achieved when Example 2 was repeated employing Wolfram disulfide, graphite,

Wolfram selenide, Wolfram telluride, lithium hydroxide, 5

zinc chloride, cobalt bromide and selenides and tellurides of molybdenum as the solid lubricant in place of the M08 4 Example 6 Equivalent improvement was achieved when Example 1 was repeated employing phosphates of Al, Mn, Zn, Mg, Ba, Ca, B, Cd, Cu and Pb in place of the iron phosphate.

That which is claimed is:

1. A lubricant composition consisting essentially of Inbricating oils or soap-thickened greases and containing in synergistic proportions (a) a solid lubricant selected from the group consisting otmolybdenum disulfide, tungsten disulfide, and calcium hydroxide and (b) an essentially water insoluble metal salt of a phosphorated oxygen acid and a metal selected from the group consisting of aluminum, iron, and calcium.

2. The lubricant of claim 1 further characterized in that the solid lubricant is molybdenum disulfide and the Water insoluble metal salt is aluminum phosphate or iron phosphate.

3. The lubricant of claim 1 further characterized in that the solid lubricant is calcium hydroxide and the water insoluble metal salt is aluminum phosphate.

4. The lubricant of claim 1 further characterized in that the solid lubricant is tungsten disulfide and the water insoluble metal salt is calcium phosphate.

References Cited UNITED STATES PATENTS 2,449,510 9/1948 Robertson 25225 2,635,078 4/1953 Stross et al. 25225 2,807,583 9/1957 Bratz et al. 252-48 2,921,899 1/1960 Sproule et al. 25221 2,964,475 12/ 1960 Morway 25218 2,967,151 1/1961 Morway 25218 3,009,875 11/1961 Rocchini et al. 252-25 3,127,346 3/1964 Oliver et al. 25225 3,159,575 12/1964 Criddle 25225 3,223,624 12/ 1965 Morway et a1. 25225 3,271,309 9/1966 Caruso 2152- FOREIGN PATENTS 526,546 6/1956 Canada. 854,850 11/1960 Great Britain.

DANIEL E. WYMAN, Primary Examiner.

I. VAUGHN, Assistant Examiner. 

1. A LUBRICANT COMPOSITION CONSISTING ESSENTIALLY OF LUBRICATING OILS OR SOAP-THICKENED GREASES AND CONTAINING IN SYNERGISTIC PROPORTIONS (A) A SOLID LUBRICANT SELECTED FROM THE GROUP CONSISTING OF MOLYBDENUM DISULFIDE, TUNGSTEN DISULFIDE, AND CALCIUM HYDROXIDE AND (B) AN ESSENTIALLY WATER INSOLUBLE METAL SALT OF A PHOSPHORATED OXYGEN ACID AND A METAL SELECTED FROM THE GROUP CONSISTING OF ALUMINUM, IRON, AND CALCIUM. 